'Mad Men' Cast Calls Creator Matthew Weiner an Idealist (Video)

Jon Hamm, Elisabeth Moss and the gang take a pop quiz on "ABC World News," and Vincent Kartheiser shows off his hiatus hairline.

Mad Men returns April 13 -- and to gear up for the first half of the final season, creator Matthew Weiner and much of the cast taped a segment on ABC's World News With Diane Sawyer.

The spot airs Thursday night, and ABC News is teasing out the sit-down with a clip of Diane Sawyer grilling Jon Hamm, Elisabeth Moss, John Slattery, Vincent Kartheiser, Christina Hendricks and January Jones on superlatives for the cast.

And the most idealistic? Weiner, himself. The cast unanimously labels the scribe behind the drama's often morally deficient characters an idealist. "I don't agree with your ideals," says Hamm.

"If you live in a dictatorship, it is an ideology," accepts Weiner.

The interview, taped during the brief break between filming of the first and final seven episodes of the last season, also shows off Kartheiser's rather hilarious hiatus hairline: a bizarre patch of stubble where his Pete Campbell receding hairline usually lingers.